Clinical behavior modification for domestic animals and household pets is a relatively new specialty in veterinary medicine and is poorly understood today by most practicing veterinarians. Prior to about 1974, the science of veterinary animal behavior was in its most rudimentary stages and the idea of treating specific behavioral problems in domesticated dogs and cats was still in its infancy. Subsequently, over the next approximately ten years (1974-1984) animal behavior modification focused mainly on behavioral shaping using techniques developed from the science of ethology (the study of innate animal behavior patterns) and similar conditioning strategies. Even in the mid-1980's the use of specific pharmacologically active substances to modify animal behavior was only just being explored and investigated. The outmoded psychopharmacological approach then employed was along lines popular in human medicine in the 1950's when neuroleptics such as chlorpromazine were first introduced for human psychotherapy. Only since about 1985 has the specific approach to pharmacologic modification of animal behavior disturbances been fully appreciated as being both possible and desirable.
The nature and depth of the problem is illustrated by a common behavioral problem in domestic cats--inappropriate elimination or urine marking. In the domestic cat, urine marking (or spraying) usually occurs in response to the stress of competition between cats; or in response to anxiety provoking interactions with people. This is a frustrating situation for cat owners; and, unfortunately, an incomplete resolution of this problem may, and often does, result in euthanasia of the cat by its owners.
It will be recognized and appreciated that the most common veterinary therapies to solve the behavioral problem of urine making include gonadectomy, environmental modification, and pharmacologic intervention [Borchelt, P. L., Compendium Continuing Education Pract. Vet. 8:197-205 (1986)]. Gonadectomy greatly reduces or stops urine marking; however, it has been reported that 10% of 134 castrated male cats and 5% of 152 spayed female cats continue to spray inappropriately following the surgery [Hart, B. L. and L. Cooper, Med. Assoc. 184:1255-1258 (1984)]. Moreover, cats are often refractory to both environmental and behavioral modification as a treatment for spraying or urine marking [Hart, B. L. and L. A. Hart, Canine and Feline Behavior Therapy, Lea & Febiger, 1985, p 134].
Among the different drugs presently prescribed as a treatment for urine spraying in cats are the progestins and the benzodiazepine, diazepam. Both of these drug therapies have had but limited success and are associated with undesirable side-effects for the animal. The progestins, medroxyprogesterone acetate and megestrol acetate, have been reported to eliminate urine marking behavior in approximately one-third of animals treated [Hart, B. L., J. Amer. Vet. Med. Assoc. 177:5229-533 (1980)]. Prolonged progestin therapy is also associated with recognized increases in appetite, body weight, and insulin levels. Progestins also have been reported to produce mammary gland hyperplasia, diabetes mellitus, acromegaly, pyometra, and adrenocortical suppression [Henik et al., Comp. Cont. Ed. Pract. Vet. 7:132-140 (1985)]. In comparison, diazepam has been shown to stop or reduce the frequency of spraying in neutered cats. However, side-effects of diazepam therapy include lethargy, temporary ataxia, and increases in appetite [Marder, A. R., Proceding of Animal Behavior Society Meeting, Raleigh, N.C., 1985]. Tolerance to the effects of the drug and physical dependence are also major problems associated with benzodiazepine therapy.
Accordingly, it is recognized and appreciated by veterinary practitioners and animal behavioral specialists that there remains a standing need for novel pharmacological treatments for a variety of animal behavior disturbances. Moreover, were a new class of pharmacologically active compounds to become available for clinical behavior modifications in domestic animals and household pets, this method would be of major advantage and maximum benefit both for the animal as well as its owner.